According
to the team, which included Government nutrition advisor Professor Susan Jebb,
from Oxford University, and Cambridge geneticist Dr Giles Yeo, each group
responds differently to different diets.

They
tested their theories on 75 volunteers – 25 from each group – over three months
last summer.

The
findings will be aired in a three-part Horizon programme, starting on BBC 2 on
January 12.

Presenter
Chris Dr van Tulleken said "feasters don’t release enough of a hormone known as
GLP1, which tells your brain you are full."

He said: "If you are someone who goes to an all-you-can-eat buffet and never feels full,
then chances are you are a feaster."

"Secondly,
we know that some people have a genetic risk factor for being overweight. It isn't one gene – there are many. Some of them are about personality, some are
about appetite, and some about willpower. Those with lots of these ‘‘obesity
genes’’ are the constant carvers."

Finally, we noticed some people
self-medicate with food. They eat when they are unhappy. We call them the "emotional eaters."

Having identified the groups, the researchers
created different diets for each.

Feasters were given a diet designed to
stimulate gut hormone levels with high-protein foods such as meat, fish and
pulses, and cut out ‘high-GI’ carbohydrates such as white bread and potatoes.

Constant cravers were put on a version
of the 5:2 diet, eating no more than 800 calories for two days every week. They
could eat what they liked for the other five.

Emotional eaters were enrolled in Weight
Watchers-style classes, on the theory that what they really needed was social
support to prevent them turning to food.Dr van Tulleken hopes the work will
help people understand what causes their weight problems and "spell an end to
fad diets."